Fig 4. Annual changes of the Impact Factor (IF) and its variables (citation versus article numbers).

For the annual changes (A-D) of the IF, the relation of relative changes of the number of citations versus articles is shown in each diagram by blue and grey columns, respectively. Each column shows the relative change (%) in relation the numbers of citations or articles in the preceding year. Below each diagram, the ΔIF for each annual step is classified ‘invalid’ as defined in Fig 3 and indicated by a red box behind the journal ID. The 49 journals in the sample cohort are identified by a unique identifier (#1 - #49).